Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 62C, § 7

Every partnership having a usual place of business in the commonwealth shall file, on or before the fifteenth day of the third month following the close of each taxable year, an information return sworn to by a member of the partnership.  Such return shall include the partnership's income or losses from sources taxable under chapter sixty-two, any deductions or credits attributable thereto, the names and addresses of the partners and the distributive shares of the various classes of partnership income, losses, deductions or credits apportioned to each, and such other information as the commissioner may require in order to determine the taxable income of each partner.